I also serve a snack after naptime between 3 - 3:30 and it's nacho chips & cheese & mangos today just to give you an idea. I agree with you that I want to give the children enough to tide them over until their busy parents have time to get them home and prepare the evening meal.

As for breakfast, I tell parents that if they arrive by 8:15 then I will serve their child breakfast, but if they arrive at 9 they must have eaten or be hungry until lunch. It is working great for me. The parents who don't drop off their child until 9 have lots of time to feed them in my opinion.

I don't think you are centering out any families if you send a letter to everyone. You are reinforcing your routines and rules and the way you run your daycare, period!